Method for coloring coal



Sept. 13, 1938. w. F. GLlNsMANN 2,129,901

METHOD oF coLonINe coAL File'd June 4, 1955 4 Sheets-Sheet 1 WHTf/P VLM ATTORNEY.

Sept'. 13, 1938.

w. F. GLlNsMANN METHOD oF oLoRn-G 'COAL 4 Sheets-Sheet 2 Filed June 4. 1935 INVENTOR.

Sept. 13, 1938. w. F. GLINSMANN METHOD 0F COLORING COAL 4 sheets-'sheet s Filed June 4, 1955 kw my i ATTORNEY.

Sept. 13, 1938. w. F. GLlNsMANN 2,129,901

METHOD oF coLonINe coAL Filod June', 1955 4 Sheets-Sheet 4.

I I NVEN TOR. /a/rf/P @4MM/wmf,

Patented Sept. 13, 193s PATENT OFFICE 2,129,901 METHOD Foa coLomNG coAL Walter Frank Glinsmann, Jersey City, N. J.,as signor to American Cyanamid Company, New York, N. Y., a corporation of Maine f Application June 4, 1935, serial No. 24,827

'12 claims.l

The present invention relates to methods for the coloring of coal and the colored coal per se as an article.

It has heretofore been proposed to apply a socalled Prussian Blue to the surface of coal buty difficulty has been encountered in commercial practice in securing a uniform and adherent color, that is, one which would stand up under mechanical handling and weathering conditions.

The primary object of the present invention is to overcome the above difficulties, to secure co1- ored coal Where the color is adherent, cannot be readily rubbed off, is resistant to weathering, is reasonably uniform, and in which coal of vvarious ages of fracture may be.so treated as to produce .efficient coloring.

To this end, one aspect of the invention contemplates the treatment`of freshly fractured coal lto produce a colored surface thereon as the age of the fracture has been found to be a material .contributing factor in the efliciency of the coloring process. Another aspect of the invention comprises the treatment of old fractured coal so as to produce the equivalent of a freshly fractured surface.

vAnother aspect contemplates the colored coal as such, as it has been found that one of the main reasons for the high degree of adherence of the color applied as in this invention, is that such color is actually formed integrally on said surface in contradistinction to color formed remote from the coal and then applied thereto. The invention further consists in the detailed methods of treatment, the apparatus for carrying out such methods and the colored coal per se more fully hereinafter shownand described.

In the drawings:

Fig. 1 illustrates a diagrammatic flow sheet in a typical treatment;

Fig. 2 shows a diagrammatic lay-out of a preferred form of apparatusv carrying out a coal coloring treatment;

Fig. 3 is a transverse section along the line 3-3 of Fig. 2;

Fig. 4 shows a diagrammatic view of a modified form of apparatus;

Fig. 5 is a sectional view along the line 5-5 of Fig. 4;

Fig. 6 is a side elevation showing a diagrammatically modified form of apparatus for th batch treatment of coloring coal;

Fig. 7 is an end view of the device of Fig. 6.

Referring now withmore particularity totheembodiment illustrated for the formation of a i blue or bronze color on coal and with reference .tumbling or shaking apparatus.

length of time in pools of the treating liquid.

to the owsheet of Fig. l, the freshly fractured coal or coal treated to produce the equivalent of a freshly fractured surface, of which more later, is

first washed to remove such objectionable material as dust, slime, mine water and/or excess 5 reducing agent and is then fed into a suitable In the case of old fractured coal, this tumbling equipment may be such'as will mechanically produce the equivalent of a freshly fractured surface, which matter will be more fully discussed hereinafter. In the case of freshly fractured coal, however, this tumbling or shaking apparatus may consist of a chute, trough, or rotary equipment into which the coal is fed and where contact is made with a coloring solution which preferably consists of a freshly mixed solution of an alkali or alkaline earthy metal ferricyanide, such as ammonium, sodium, potassium or calcium ferricyanides and a ferric salt solution, such as chlorides, nitrates or sulphates. It is preferable that the tumbling or shaking apparatus, which may be termed a contact apparatus, be provided with means whereby the coal to be treated remains for a requisite From this contact apparatus the spent liquid may be drained for re-use if found desirable and the coal so. treated andl colore'd is then passed to a washing apparatus and from thence -to storage or coal cars for delivery to the consumer. As a matternof fact, the washing subsequent to the coloring treatment may take place remote from the coloring apparatus, either prior to storage, subsequent to storage, prior to loading into the cars or subsequent thereto as circumstances will dictate.

As to the matter of the desirability of freshly fractured surfaces fortreatment with the color-v ing solutions of this invention, it has been found that the greater the interval between fracture an'd coloring, the less efficient the blue coloring action. This is especially true as vto the rate of coloring. This retardation is especially noticeable when the interval approaches an hour. Suchcoal has a tendency to acquire a bronze effect rather than a blue color. A study of this situation has disclosed that during this period an `oxidation of the coal surface or conversion of the atomic carbon to molecular, has takn place to such an extent that the proper reaction between such surface and the coloring" solution does not produce an eiciently adherent or uniform' blue. f This result'maybe avoided either by treating coal which has., been fractured less than thatperiod of time or by treating coal which has been `fractured more than that the above circumstances.

Among the materials which have been found to be efficacious in the production of a coal surface equivalent to one freshly fractured may be mentioned reducing agents generally and specifically a solution of sodium bisulphite, sodium sulphite, sulphurous acid, stannous chloride and/or a liquid containing freshly generated hydrogen such as a suspension of finely divided iron in hydrochloric acid. Of these materials, sodium bisulphite is preferred. It is, of course, understood that any metallic salt of these acids may be likewise used in the reducing solution although the sodium salt is preferred from the standpoint of cost. While various concentrations of these reducing agents have been found to'be suitable for the purpose, yet a 10% solution has been found to give optimum results. Likewise, the time limit of contact between the reducing agent and the coal may be varied dependent upon ythe use of the reagent employed and many other circumstances. The time element shouldbe sufficiently long, however, to produce a desirably reduced surface.

It is important that the excess reducing agent be washed from the coal and this is also true of any dust, slime, mine water or other material which might effect the reaction between the'coloring solution and the coal be removed prior to the coloring treatment. Of course, if old fractured coal is to be treated with a reducing material, it is desirable that these extraneous materials be washed .from such coal prior to the reducing treatment.

The freshly fractured coal or coal having a.

surface equivalent to that of a fresh fracture may then preferably be fed, as in Fig. 2, from a hopper I into a trough 2 suitably supported as at 3 for vibration as by means of an eccentric 4 and suitable connecting mechanism 5. As the coal is fed into the trough 2, a Wash spray 6 may be provided for removal either of the dust .and slime and other objectionable material 'which may include the excess reducing agent, the wash water passing through the perforated sectionl of the trough 2 into the wash drain 8 for disposal.

The remainder of the trough 2 beyond the dewatering section is preferably provided with a series of baffles 9 forming depressions therebetween so that'the coal in passing through this shaker chute will lie not only in a plurality of layers, but in independent pools of the reagent.

supplied by means of one or more sprays IIJ. As above described, it is desirable that this reagent consist either of alkali or alkaline earth ferricyanides freshly mixed with a vsolution of ferric salts immediately prior to the application to the coal. A suitable mixture has been found to be one consisting of 0.5% ferric chloride and 0.413% calcium ferricyanide freshly mixed and supplied in the proportion of not more than x80 pounds of the mixture to each ton of coal treated.

.The shaker chute is provided at the end thereofv with a perforated section Il through which the excess material will drain due to the inclination of the chute into the drainagel equipment I2 for .proper disposal.

The coal thus treated'passes out of the end of the chute 2 into the wash means I3 supplied with a wash spray I4 where.

any excess coloring solution is removed. 'Ihe Wash water drains from this equipment through the pipe I5 for disposal. This washing step may, of course, be immediately adjacent the end of the coloring equipment, or, on the contrary, may be at some remote point, either prior or subsequent to the storage bins or prior or subsequent to the loading into cars, as found desirable. This later treatment has been found to be particularly desirable as to some types of coal as the longer the treating solution remains in contact with the coal, the better the coloring eifect. In the drawings, therefore, the washing equipment is to be taken as a diagrammatic showing as to location.

Another form of suitable equipment is shown in Fig. 4 to consist of a comparatively deep trough I6, all other parts of this equipment being substantially the same as shown in Fig. 2. In this case, however, the fact that the trough is deep as compared to its width increases the depth of the coal layer and the consequent percolation of the reagent increases the coloring efficiency.

In Fig. '6, a batch equipment is illustrated as'^ consisting of a rotary drum I1 provided with the removable manhole or cover I8 into which the material or coal to be treated may be fed through the hopper I9, the two reagents being fed from the tanks 2l) and 2I`by means of pumps 22 and controlled by means of the valve 23. A perforated pipe 24 arranged axially of the drum provides for the spraying of this mixed reagent onto the coal. Upon charging the drum with a requisite amount of coal and reagent, the valve 23 is closed'and the drum rotated through a suitable motor mechanism 25 for a requisite length of time, whereupon the manhole I8 may be removed, the drum rotated until the opening covered by the manhole is over the discharge hopper 26 Vand the batch discharged. Of course, proper washing and draining apparatus is provided as in the case of Figs. 2 and 4.

It has been found to be unnecessary to confine the batch rotary treatment of Fig. 6 to freshly fractured coal for it has been discovered that old fractured coal, when treated according to this method, acquires a surface, equivalent to that of a fresh fracture.. This may be due to the tumbling action of one piece of coal on another. At any rate, it is not necessary to especially treat coal fed to this tumbling equipment, although, of course, it may be, if so desired.

In devices of the type shown in Fig. 6, it has been found desirable 'to use a solution containing 0.5% ferrie chloride and 0.413% calcium ferricyanide, freshly mixed, in a proportion of about 46 pounds of the mixed solution per ton of coal treated. i

In all of the above treatments, it is desirable that the treating solutions be maintained out of contact with metal and this is particularly true if thev ferricyanide and ferric salt solutions are mixed' prior to the application to the coal. .For this reason, all surfaces coming in contact with such solutions should be non-metallic and be made of such materials as rubber, wood, wood coated with non-metallic containing films such as a synthetic drying oil resin, porcelain or glass, although rubber is preferred.

Coal treated according to the above process and in the above apparatus has been found to have an `admirably adherent and uniformly colored the fact that the color is not an applied lm as has been the case heretofore but, on the contrary, integral with the coal surface, that is, the coal surface itself plays a part in the reaction involving the treating reagent so that the blue color or precipitate actually forms on the surface. This is a new principle of coal coloration.

Mention has been made above that if the time interval between fracture and coloring is prolonged, a bronze eiect is produced rather than blue. In some instances, of course, it may be found desirable to produce a bronze color, in which event, either the time interval between fracture and coloring may be deliberately delayed, the reducing treatment may be omitted or the type of apparatus used may be chosen because of its inability to produce the equivalent of` a freshly fractured surface such as the tumbling equipment of Fig. 6.

In the claims, where the Words "freshly fractured surface are used this is intended to cover any situation where either the coal is freshly fractured so as to make available the substantially atomic carbon of this surface for the reaction, or the equivalent thereof such as is produced either by the use of a reducing agent or by tumbling.

While the invention has been shown and described With reference to particular steps in methods, composition and proportion of ingredients and specific embodiments of apparatus, yet it is to be understood that the invention is not to be restricted thereto but is to be construed broadly and limited only by the scope of the claims.

I claim:

1. A method of coloring coal which includes subjecting a freshly fractured coal surface to the action of an alkali or alkaline earth ferricyanide and a ferrie salt.

2. A method of coloring coal which includes subjecting a freshly fractured coal surface to the action of an alkali or alkaline earth ferricyanide and a ferric salt and subsequently Washing said coal.

3. A method of coloring coal which includes subjecting coal to a, treatment to produce a surface thereon equivalent to a freshly fractured surface and subsequently coloring said coal by applying to said surface an alkali or alkaline earth ferricyanide and a ferric salt.

4. The method of claim 3 in which the coloring material consists of a mixture of 0.5% ferri'c chloride solution and 0.413% calcium ferricyanide solution in a proportion of not more than pounds of the mixture to each ton of coal treat-ed.

5. The method of claim 3 in which the coloring material consists vof a mixture of 0.5% ferric chloride solution and.0.413% calciumferricyanide solution in the proportion of substantially 46 pounds of the mixture to each ton of coal treated.A

6. 'Ihe method of claim 3 in which said treatment comprises washing with a reducing agent.

7. 'I'he method of claim 3 in which said treatment comprises washing with a reducing agent as a 10% solution.

8. The method of claim 3 in which said treatment comprises washing with a solution containing a material chosen from the group consisting of sodium bisulphite, sodium sulphite, sodium sulphide, sulphurous acid, stannous chloride and freshly generated hydrogen.

9. The method of claim 3 in which said treatment comprises washing with a solution of sodium bisulphite. n

l0. The method of claim 3 in which said treatment comprises washing with a 10% solution of sodium bisulphite.

l1. A method of coloring coal which includes agitating and tumbling said coal to produce a surface thereon equivalent to a freshly fractured surface, and subjecting such coal surface to the action of an alkali or alkaline earth ferricyanide and a ferric salt.

12. The method of claim 1 in which the time interval between the coal fracture and the application of the ferricyanide and chloride is not greater than one hour.

WALTER FRANK GLINSMANN. 

